At first I would say it's your equipment but that might not be the case, when doing a lot of beta testing we found that a lot of brands out there were not very reliable out of the box.
First thing to try would be updated drivers if that doesn't help try updating the firmware for the router.
Next change your IP scheme.
after that you could try and set up your security from scratch start with nil security and see if you still have problems if you do, go buy Lynksys if not start adding layers at a time.